The present invention relates to a carrier tape and cover tape used for packaging and transporting components. More particularly, the present invention is directed to a cover tape that protects components placed in the cavities of the carrier tape. A foam layer is attached to the underside of the cover tape for protecting the components in the cavities of the carrier tape during transport or xe2x80x9cdrop testing.xe2x80x9d
In the electronic circuit assembly field, electronic components such as semiconductor chips, devices, integrated circuits, and the like are generally packaged and transported in carrier tapes from one manufacturer to another manufacturer or customer. It is often critical that the components be packaged and transported with minimal damage. By their very nature, these electronic components are lightweight objects and susceptible to damage and accordingly, it is important that these components be packaged and transported in a manner that minimizes/eliminates damage to them. After manufacturing the electronic components in a xe2x80x9cclean roomxe2x80x9d facility, the components are generally packaged and transported to a customer such as a computer wholesaler to mount them onto printed circuit boards.
The semiconductor fabrication industry currently implements a JEDEC standard carrier tape system to package and transport semiconductor components. Conventional carrier tape systems allow the component manufacturers to package and transport the components to their customers, while allowing the customers to efficiently unload the components using a robotic or automated pick and place machine.
FIGS. 1A-1B illustrate various views of a conventional carrier tape system. FIG. 1A illustrates a perspective view, and FIG. 1B illustrates a cross sectional view taken along line Ixe2x80x94I of FIG. 1A of the conventional carrier tape system. Reference will be made to FIGS. 1A-1B concurrently for a more complete understanding of the conventional system.
A conventional carrier tape 2 includes multiple thermoformed pockets or cavities 4 formed along its longitudinal direction for storing and transporting the components 6. The carrier tape 2 also includes a row of advancement holes 8 formed longitudinally along one side of the carrier tape 2 for locating and feeding the components 6 to the automated pick and place machine (not shown).
During the packaging process, the components 6 are loaded into the cavities 4 of the carrier tape 2 by the automated pick and place machine. After the components 6 are successfully loaded into the cavities 4, a cover tape 10 is applied over the cavities 4 using, for example, a sealing iron (not shown) to secure the components 6 contained therein. The cover tape 10 prevents the components 6 from exiting the cavities 4 of the carrier tape 2. The cover tape 10 is heat bonded over the carrier tape 2 on the bonding zones 12 along the longitudinal direction. After sealing the cavities 4 of the carrier tape 2 with the cover tape 10, the components 6 are transported to another manufacturer/customer.
The electronic component 6 typically includes multiple leads 20 extending from two opposite sides, as illustrated in FIGS. 1A-1B. In some instances, the leads 20 can extend from all fours sides of the component 6. The leads 20 are fragile and can be easily damaged with minimal contact. In most instances, the cavities 4 are formed in a specific manner depending on the dimensions/design of the component 6 for supporting and protecting the components 6 or leads 20 from damage. However, each component 6 design and dimension requires a unique cavity design. Furthermore, it is well known in the industry that the components 6 are still damaged using these specially designed cavities.
FIG. 2 illustrates a conventional packaging system used in the electronic circuit industry. As discussed above, the components 6 are placed in the cavities 4 of the carrier tape 2 before the components 6 are secured with the cover tape 10. The loaded carrier tape 2 is then wound into a roll or a reel 30 (xe2x80x9creelxe2x80x9d hereinafter). The carrier tape 2 and cover tape 10 are made of materials sufficiently flexible to be wound into the reel 30, which materials are described in more detail later herein. After the carrier tape 2 is wound on the reel 30, the reel 30 can be placed within a static control bag before it is placed in its individual box. Thereafter, one or more individual boxes can be placed in a shipping box for storage and transport to another manufacture or customer.
After receiving the shipping box, the reel 30 is unpacked from its individual box and the static control bag. The carrier tape 2 is then unwound from the reel 30 and is positioned on the automated pick and place machine. As the carrier tape 2 advances in a longitudinal direction using advancement holes 8, the automated pick and place machine simultaneously removes the cover tape 10 and picks up the components 6 from the cavities 4 and places them in desired locations (e.g., mounts them to printed circuit boards).
The electronic circuit industry conducts a xe2x80x9cdrop testxe2x80x9d on the final packaging system. As described above, the final packaging system includes the reel 30, carrier tape 2, cover tape 10, and components 6. Again, the packaging system can also include the static control or vacuum-sealed bag, individual and/or shipping boxes for receiving the reel 30. During drop testing when the packaging system is dropped intentionally, it is reported that a great number of components 6 sustain damage using current packaging technology. Most likely, the leads 20 bend from the rapid deceleration of the components 6 against the vertical sidewalls of the cavities 4 after the components 6 xe2x80x9cjump.xe2x80x9d Specifically, the components 6 xe2x80x9cjumpxe2x80x9d within the cavities 4, and the leads 20 collide with the vertical sidewalls, thereby causing the leads 20 to bend. Damage can also result within the components as a result of such collision. It can be appreciated that the conventional carrier tape system does not sufficiently protect the components 6 from damage during drop testing or transport. Achieving minimal component 6 damage is often very difficult and continues to be a major problem in the carrier tape industry.
Undulations may also result in the carrier tape 2 as the components 6 are transported from one facility to another. Such undulations may undesirably change the placement of the components 6 in the cavities 4 of the carrier tape 2, thereby leading to obstructions in using the automated pick and place machine.
Accordingly, there is a need for a packaging system and method designed to protect the electronic components from damage, and particularly, protecting the leads from bending or crushing. There is also a need for a packaging system and method for preventing undulations of the components in the cavities of the carrier tape during transport.
It is an object of the present invention to provide an apparatus and method for protecting electronic components from damage during transport or xe2x80x9cdrop testing.xe2x80x9d
It is another object of the present invention to provide a cover tape that protects electronic components placed in the cavities of a carrier tape.
It is a further object of the present invention to provide a cover tape having a foam layer attached thereto for protecting electronic components in the cavities of the carrier tape.
It is yet another object of the present invention to provide a packaging system and method designed to protect the leads on electronic components from damage.
It is another object of the present invention to provide a packaging system and method for preventing undulations of the electronic components in the cavities of the carrier tape during transport.
The present invention relates to a packaging system and method for protecting electronic components from damage during transport or xe2x80x9cdrop testing.xe2x80x9d The packaging system of the present invention includes a novel cover tape bonded to a carrier tape. A foam layer is attached to the underside of the cover tape for protecting the electronic components that are stored in the cavities of the carrier tape. The foam layer prevents excessive movement of the components in the cavities, thereby protecting the leads and other parts of the electronic components from damage. The foam layer is preferably made of a material that is flexible, static resistant, and not susceptible to generating residuals.
The method for protecting the components in the cavities of the carrier tape includes attaching the foam layer on the underside of the cover tape before sealing the cover tape on the carrier tape. The foam layer can be attached to the cover tape using adhesives. When the cover tape is bonded to the carrier tape with the components placed in the cavities, the foam layer is positioned on top of the components. In this manner, the components do not move excessively within the cavities and is protected by the foam layer.
In another embodiment, the foam layer can be attached to the underside of the cover tape as the cover tape is being bonded to the carrier tape. In both embodiments, the foam layer protects the components from damage. In addition, the foam layer also acts to prevent undulations from occurring.